Building a carbon dioxide storage portfolio for the Barrow-Dampier sub-basins through regional screening – an integrated geoscience approach

Abstract

Safe geological carbon dioxide (CO₂) storage (GCS) requires rocks with suitable injectivity, capacity and sealing properties to ensure secure long-term containment of injected CO₂. A regional understanding of the subsurface is essential to determine the potential for GCS of a basin and to select target sites. This is best addressed by integrating the basin’s tectono-stratigraphic evolution, its gross depositional environment, and its hydrodynamic, thermal and stress regimes. A basin-scale GCS assessment for the Barrow-Dampier sub-basins was conducted by Geoscience Australia and SLB. The objective of the study is to high-grade geological intervals and sites for potential GCS and to understand potential storage capacity and key risk factors. Stratigraphic and structural mapping of key storage intervals was performed using the reprocessed seismic volume and well database associated with the project. Analysis of critically stressed faults was used to estimate the likelihood of reactivation based on the far-field regional stress field and fault mechanical properties. Pressure, temperature, porosity, permeability, and water geochemistry data have been screened for >500 wells for assessing the storage unit intervals and predicting the hydrodynamic regime. Calibrated 2D basin models provide information on the regional pressure-temperature regime, porosity/permeability distribution, and sealing effectiveness. Potentiometric surface maps for the aquifer systems inform the distribution of potential CO₂ plume migration. Results of this integrated regional basin study are used to quantify the risk of identified storage containers and to map the chance of success for GCS at a regional scale. The project results are publicly available via NOPIMS.